Done getting bit in the ASS by toe brakes

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Posted

Been bitten in the mass by my Kifoxes toe brakes three times. First time was a ground loop that bent the landing gear. Bought a set of wide bungee gear to replace the stock gear. Second time got two blades of the three blade WARP DRIVE prop. Bought a POWER FIN 3 blade to replace it. Third time, ran off a dirt road onto the shoulder, luckily didn't hurt anything this time.

Had a BLACK MAX hand brake in the parts bin. Finished the installation today. (See attached). Taxied today. Brakes are a little soft, but are a whole bunch better than the toe brakes. The hand brake held to 5000 RPM. No differential braking, but that's better than brakes on when landing. Test flight tomorrow.

Rick

P_20190730_155340_1.jpg

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Posted

Could you clarify a little more on how the brakes were involved?  Sticking brake, dragging brake, brake lockup, etc. ? I thought about using Black Max 1500's on my fox when I decide to replace the original enginetics brakes, which work great.

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Posted (edited)

Congratulations on making a more effective braking system, but in my humble opinion ground loops are caused by bad rudder action, and brakes are a way to try and fix a problem that was created by the slow feet.

But on the other hand your stick lever looks great, take a look at some of Fred Stork's posts, he installed a dual brake handle system on his airplane so he has differential hand breaks.

Edited by nlappos
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Posted

They make that same handle with two levers so u can have differential brakes, and its about the same size. 

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Posted

I had a set of twin handles on another plane and they worked good. Of course they were cable bakes. In this case you would need another master cylinder. Is there room to mount a second cyl.? One could adapt the old toe brake master cylinders to work with a little thought. I do see a few brake handles mounted in the center between the seats or in that area. Actually didn't like them at first glance but brake handles between the seats seemed natural when I tried them. Unless your doing a lot of STOL stuff, shouldn't be an issue.

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Posted

I'm glad you found something that works for you.  I would probably crash trying to use them since my hands tend to be pretty busy with throttle, flaps and stick.

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Posted (edited)

Congratulations on making a more effective braking system, but in my humble opinion ground loops are caused by bad rudder action, and brakes are a way to try and fix a problem that was created by the slow feet.

But on the other hand your stick lever looks great, take a look at some of Fred Stork's posts, he installed a dual brake handle system on his airplane so he has differential hand breaks.

I have tried all versions by now: pure toe brakes, mono hand brake on the stick, double hand brakes on the stick, toe brakes coupled with mono hand brake (this was the theoretically most pleasing solution) and finally mono hand brake on the stick and a switch for braking on only one side. 

I agree that ground loops should be due to bad rudder action and that differential brakes are there to save the situation. But I find the reality being the opposite. It is very hard to be brake in a “creative “ fashion with the toe brakes while still working the rudder. Some can do it, but most will fail when they are half way into a ground loop. And while it can happen to anyone it is less frequent for the experts...

This is why I, not an expert, prefer having easy access to powerful, while still easy to dose, equal braking. My solution is a main (motorcycle) brake handle on the stick. Moderate brake an rudder still allows for fairly precise maneuvers and I can brake hard when needed without the risk of being to hard (ground loop...) on one side. And, for tight situations I have a switch that direct all the brake power (fluid) to only one side making it easy to turn around one wheel (a flashing light tells me the switch is engaged to avoid leaving it there for landing...)

 

Edited by FredStork
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Posted

what about heel brakes?

at my flight school of choice (all taildragger Jodel aircraft) we had retro-fitted scott heel-brakes with cleeveland brakes on all aircraft when i started flying. i found them pretty controllable and quite easy to avoid while working the rudder (just hold your heels together and you're good :)).

the school has converted to toe brakes and has had two ground loops since then (in 2 years) ... they had about the same number of ground loops in the same aircraft since purchase with the heel brakes before, only that was over a period of about 10 years or so.. I personally don't like the toe brake setup in those aircraft as i am pretty tall and the space down there is quite limited and the toe brakes certainly don't help with that.

the SOP from the school is, to keep your tows off the toe brake bar (it is a pipe that sits above the rudder "peddal" pipe, like in the Avid), until the aircraft touches down, then the pilot is supposed to move his heels forward, or his tows upward.. to transition to lateral control via the toe brakes.. once this transition is made, lateral control happens mainly through the brakes and no longer throug rudder imputs. the SOP further demands to slow down the aircraft ASAP after touch down, to shorten the high-speed taxi time which is obviously the most ground-loop prone period of the landing.

in the last incident report by our swss NTSB regarding the last ground loop (which happened during a PPL skill test!, i guess he failed), they found that the ground loop was probably initiated right during this transitioning forward with the feed to reach the toe brakes. due to the mounting angle of the toe brake pedals onto the rudder pedals and the angle at wich a taller person must hold their feed it is not possible for tall people to just slide forward without letting go of the rudder for a second.. if your tail decides to drift away during this second, you might be too late by the time you are on the brakes.

my take on this is: in a tight  tailwheel aircraft, toe-brakes need to be installed at exactly the right angle relative to the rudder pedals, so that the pilot can simply slide forward with his feet without loosing rudder control or accidentally pressing the toe brakes during rudder inputs. when at the right angle. this should be possible for experimental aircraft that are operated only by one person or where all pilots are the same size.. in any other case, some other brake setup might work better. as for the flight school i think they should have kept the heel brakes instead..

On my previous aircraft (also a Jodel, same type as the school was ground-looping) i have the original setup of the french aircraft manufacturer: the rudder is linked to the brake on the respective side. The brakes only start reacting towards the end of the rudder movement. For slowing down the aircraft, there is a brake handle which actuates both master cylinders at the same time with equal force to slow down the aircraft. This setup is amazingly easy to land and take-off with and i quite liked it. the only downside is, that you loose a little bit of rudder movement during landing and take-off roll.. and it needs to be setup very precisely so the brakes don't kick in too early, this usually means more maintenance on the brake setup as it needs to be re-adjusted every now and then, which understandably whas a nightmare for a flight-school where the brakes wear off fast due to all those practice laps.. I almost went into the fence during a take-off due to that.. when I bought the airplane, the brakes where linked too firmly with the rudder. During a takeoff on a realtively long runway a crosswind gust hit  me at about 80% of my take-off-roll.. i reacted with the appropriate rudder input which caused the brakes to kick in and therfore slowed down the airplane significantly increasing my take-off roll tremendously.. that was my most exciting take-off so far! but now that it's all set up nicely, i can land my airplane without thinking about brakes, they are just there when i need them and they do their job :)

on my avid i am considering to install some heel brakes, as they are mechanically alot easier to install and need less maintenance (adjustment) as one can "feel" the right amount of input pretty easily. To keep the toe brakes i'd need to advance the lower bump in the firewall further forward to make some more room so i can set up my rudder pedals and toe brakes at a flatter angle as i'm too tall to operate them otherwise. (6ft tall, shoe size 12, not really stock avid model 3 dimensions).

cheers

Pascal

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Posted

The brakes caught me out the other day on my Avid.

A thermal caught me as I touched down and kinked the plane a little to the left, full right rudder applied but I kept going left!! Unfortunately I went off my airstrip onto some rough ground so a wingtip went down and the flaperon touched the ground. The wing is now stripped of covering and I'm doing the repairs.

Not a ground loop as I basically went straight but at 20 degrees to the strip.

I don't have much time on the Avid but have about 700 tailwheel hours and am in current practice with a Chipmunk so my feet are not dead.

My analysis is that full right rudder brings the left brake forward and unless one has the presence of mind to lift the left foot then the brake is applied. As the aircraft slows the rudder becomes less effective but the brake doesn't!!

Basically the brake pedal geometry sucks.

I am thinking that valves on the pedals and a lever on the stick would give good differential braking and be similar to the setup on the Chipmunk.

Ken

IMG_2083.JPG

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Posted

Ouch!  that hurts to just look at it.  It can be fixed though, so that's a good thing.  JImChuk

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Posted

Ken

That's exactly what happened to me on my first incident. Didn't get the wing, just bent the left main gear. The only way you could see the bend was with a straight edge. For the second, I was on final about Five feet in the air. A dust devil was going across the runway. The airplane fell out of air when I hit the dust devil. I inadvertently had both brakes applied. Got about a quarter inch of two of the three blades of my Warp Drive prop. The third, I didn't hurt anything on the airplane. Landing on a dirt road. Airplane started drifting right. Corrected with left rudder, but had right brake applied. Realized had right brake on, took right foot off the pedal and applied full left and brake. Airplane stopped on shoulder, 90 degrees to the road. Shut down, got out, nothing bent. Flew home and started on the hand brake the next day. No differential braking, but the hand brake holds the airplane at 5000 static. I'm happy with the setup.

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Posted

Sorry to see your bird bent, yes the std brake setup isn't the best. My fox 3 had a similar setup so I adjusted the brake peddles forward ( toward the bulkhead) as much as possible. The later 4,s have a better setup, whether this is practical to retrofit a similar system so the "active" brake becomes more effective when the rudder is being used.

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Posted (edited)

One nice thing about moving the brakes to a hand brake on the stick is, at least on the earlier Avids, is the possibility of more legroom, and better ergonomics. With the brake components gone from the pedals, the pilot-side rudder pedals can be clocked forward maybe 10 degrees or so.  The passenger-side rudder pedals can't be clocked forward,, as there's no bulge for master cylinders.

Edited by Turbo

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Posted

So what happens when you come in to land in a stiff cross wind and need differential braking to straighten you out?  That single hand brake will not offer you any more protection from a ground loop in fact it will compound the problem because applying the brakes will override any rudder inputs you may have had. If you are going to use a hand brake I would recommend installing a differential system. 

I had a differential cable hand brake system on my first Avid and it worked well. It was mounted to the face of the center seat cross member to the left of your left leg. Bad thing was it took your hand off the throttle.

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Posted

My experience with brakes and tail wheel is the brakes didn't cause the ground loop.

I was taught "toes off the pedals" during landing. I've had to add brakes with a stiff cross wind, but that was a Citabria with huge pedals.

My Matco brakes work fine, holds a full throttle run up, even picking up the tail. That's with the small tires though.

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Posted

Congratulations on making a more effective braking system, but in my humble opinion ground loops are caused by bad rudder action, and brakes are a way to try and fix a problem that was created by the slow feet.

But on the other hand your stick lever looks great, take a look at some of Fred Stork's posts, he installed a dual brake handle system on his airplane so he has differential hand breaks.

I have tried all versions by now: pure toe brakes, mono hand brake on the stick, double hand brakes on the stick, toe brakes coupled with mono hand brake (this was the theoretically most pleasing solution) and finally mono hand brake on the stick and a switch for braking on only one side. 

I agree that ground loops should be due to bad rudder action and that differential brakes are there to save the situation. But I find the reality being the opposite. It is very hard to be brake in a “creative “ fashion with the toe brakes while still working the rudder. Some can do it, but most will fail when they are half way into a ground loop. And while it can happen to anyone it is less frequent for the experts...

This is why I, not an expert, prefer having easy access to powerful, while still easy to dose, equal braking. My solution is a main (motorcycle) brake handle on the stick. Moderate brake an rudder still allows for fairly precise maneuvers and I can brake hard when needed without the risk of being to hard (ground loop...) on one side. And, for tight situations I have a switch that direct all the brake power (fluid) to only one side making it easy to turn around one wheel (a flashing light tells me the switch is engaged to avoid leaving it there for landing...)

 

Hello Fred,

could you let me know more about the valve that you used to select left/right braking please, is it a solenoid valve or just manual. 

Ken

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Posted

Landing gear is a big part of this equation. I bought the Highwing LLC gear, and find the entire ground handling world to be different. Wider, higher and much more positive yaw control on rollout.

image3.jpeg

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Posted

Congratulations on making a more effective braking system, but in my humble opinion ground loops are caused by bad rudder action, and brakes are a way to try and fix a problem that was created by the slow feet.

But on the other hand your stick lever looks great, take a look at some of Fred Stork's posts, he installed a dual brake handle system on his airplane so he has differential hand breaks.

I have tried all versions by now: pure toe brakes, mono hand brake on the stick, double hand brakes on the stick, toe brakes coupled with mono hand brake (this was the theoretically most pleasing solution) and finally mono hand brake on the stick and a switch for braking on only one side. 

I agree that ground loops should be due to bad rudder action and that differential brakes are there to save the situation. But I find the reality being the opposite. It is very hard to be brake in a “creative “ fashion with the toe brakes while still working the rudder. Some can do it, but most will fail when they are half way into a ground loop. And while it can happen to anyone it is less frequent for the experts...

This is why I, not an expert, prefer having easy access to powerful, while still easy to dose, equal braking. My solution is a main (motorcycle) brake handle on the stick. Moderate brake an rudder still allows for fairly precise maneuvers and I can brake hard when needed without the risk of being to hard (ground loop...) on one side. And, for tight situations I have a switch that direct all the brake power (fluid) to only one side making it easy to turn around one wheel (a flashing light tells me the switch is engaged to avoid leaving it there for landing...)

 

Hello Fred,

could you let me know more about the valve that you used to select left/right braking please, is it a solenoid valve or just manual. 

Ken

2 manual valves, in the middle position they are both half open, when one is closed the other is fully open as they are mounted mirrored to each other

image.thumb.jpeg.d506bbb6bf605bbf9d9880d

they are operated with a knob close to the throttle (that I have on my left hand side exactly where my left hand falls)

image.thumb.jpeg.0592ebd80316c51c252fa56

and I have one single valve, placed before the double valve, for parking brake. Works great...

image.thumb.jpeg.92bb09778c091d925878e8d it is the same kind of valve as the others.

I hope this helps!

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Posted

Very similar to the fuel selector valve in my 1959 Cessna 172 - a simple cam-driven ball valve. I would think it would work well for this application.

 

Image result for early cessna 172 fuel selector valve

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Posted

I have my toe brakes angles slightly forwards.  I have never had an issue of getting on the brakes unless I wanted to.  

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Posted

So what happens when you come in to land in a stiff cross wind and need differential braking to straighten you out?  That single hand brake will not offer you any more protection from a ground loop in fact it will compound the problem because applying the brakes will override any rudder inputs you may have had. If you are going to use a hand brake I would recommend installing a differential system. 

I had a differential cable hand brake system on my first Avid and it worked well. It was mounted to the face of the center seat cross member to the left of your left leg. Bad thing was it took your hand off the throttle.

I'm not sure I have the skill to pull that off.  For this old man, things seem to happen faster.   I always land without braking, then try to apply them equally to slow the airplane down.  A single master cylinder would cure the issue of uneven braking and its negative effects under normal circumstances.  If the runway is sufficiently wide, one might consider landing diagonally on it to lessen the crossflow component.

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Posted

So what happens when you come in to land in a stiff cross wind and need differential braking to straighten you out?  That single hand brake will not offer you any more protection from a ground loop in fact it will compound the problem because applying the brakes will override any rudder inputs you may have had. If you are going to use a hand brake I would recommend installing a differential system. 

I had a differential cable hand brake system on my first Avid and it worked well. It was mounted to the face of the center seat cross member to the left of your left leg. Bad thing was it took your hand off the throttle.

I'm not sure I have the skill to pull that off.  For this old man, things seem to happen faster.   I always land without braking, then try to apply them equally to slow the airplane down.  A single master cylinder would cure the issue of uneven braking and its negative effects under normal circumstances.  If the runway is sufficiently wide, one might consider landing diagonally on it to lessen the crossflow component.

The Avid is good at crosswinds landings. If you would need both rudder and brakes to keep straight you could probably do a really short cross the runway landing instead. Being precise with rudder and differential brakes is very difficult. 

The ideal theoretical solution is differential brakes on the pedals and master on the stick - I, however, never got it to work correctly due to the difficulty is getting a good geometry on the pedal/cylinder. 

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Posted

Very similar to the fuel selector valve in my 1959 Cessna 172 - a simple cam-driven ball valve. I would think it would work well for this application.

 

Image result for early cessna 172 fuel selector valve

Yes, any valve that can do open "only left", "only right" and "both" will do. If it also have all "off" it will do parking brake as well.

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Posted

So what happens when you come in to land in a stiff cross wind and need differential braking to straighten you out?  That single hand brake will not offer you any more protection from a ground loop in fact it will compound the problem because applying the brakes will override any rudder inputs you may have had. If you are going to use a hand brake I would recommend installing a differential system. 

I had a differential cable hand brake system on my first Avid and it worked well. It was mounted to the face of the center seat cross member to the left of your left leg. Bad thing was it took your hand off the throttle.

Re-reading paragraph 5 of Ken Kelso's blog brings a significant issue to light.  This may well be why using differential braking to stop a groundloop with our stock toe-brake setup is so difficult.  The toe brakes exacerbate the problem instead of helping.  

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Posted

Turbo

That's what happened to me 2 of the 3 times the toe brakes bit me. The third time, my size eleven shoes where on the brakes when landing. I learned how to fly in a Champ with heal brakes. Owned a 41 Luscombe with heal brakes. Owned a 46 Cessna 140 with toe brakes. Was a crew chief on F111s, F4s and C130s, and you had to move your feet to apply brake on all of them. Over 400 hours in taildragers. The Kitfox is a great airplane. Love flying it. The brake pedal geometry sucks. So I took out the toe brakes and installed the hand brake. And the hand brake holds up to 6000 RPM. Black max makes a differential hand brake that I might change to this winter.

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